1. Technical Field
The present disclosure relates to a method of forming a silicon layer and a method of manufacturing a display substrate using the same. More particularly, the present disclosure relates to a method of forming a silicon layer, which is capable of improving crystalline fraction and uniform grain distribution of a silicon crystal, and a method of manufacturing a display substrate using the same.
2. Description of the Related Art
The technology for electronic display apparatuses and liquid crystal display apparatuses including a thin film transistor have been significantly improved. For example, a liquid crystal display (LOD) apparatus having an all color display has been devised, so that the LCD apparatus has substantially the same color reproducibility as a cathode ray tube (ORT) display apparatus. A large-screen display substrate includes a thin film transistor using an amorphous silicon (a-Si:H) as a semiconductor layer. The amorphous silicon (a-Si:H) is relatively inexpensive and provides improved electric characteristics for the LCD device, and thus a thin film transistor utilizing the amorphous silicon (a-Si:H) is typically used for an active matrix LCD apparatus as a pixel charge device.
Moreover, to increase contrast ratio, uniformity of color, high brightness viewing angle, and resolution, a display device including an organic light emitting diode and a light emitting diode including a polymer material has been developed.
As a result, the material characteristics of the semiconductor layer used in the thin film transistor for an active matrix display apparatus have been improved. Thus, higher stability and faster charge characteristics than those obtained from a amorphous silicon (a-Si:H) are now needed.
Microcrystalline silicon is a semiconductor material used to form a semiconductor layer. A semiconductor layer formed using microcrystalline cellulose has various characteristics such as high mobility and high stability.
The microcrystalline silicon layer is typically formed through a plasma enhanced chemical vapor deposition process (PECVD) using a mixed gas. However, to use a microcrystalline silicon layer to form the semiconductor layer of the thin film transistor, the silicon crystals of the microcrystalline layer should have increased size, improved uniformity of distribution and improved fraction. Moreover, a larger silicon crystal size is also preferred. However, the size uniformity of the crystals is more significant than the size of the crystals.
The plasma enhanced chemical vapor deposition process used for forming a microcrystalline silicon layer should be an optimized process condition such that a silicon layer having improved electric characteristics compared to an amorphous silicon layer of a thin film transistor is formed. For example, the process conditions of a plasma enhanced chemical vapor deposition process may include a plasma power, a chamber pressure, a temperature of a substrate, an amount of reaction gas, a gap between an electrode and the substrate, a deposition time and so on.
Thus, there is a need for a method of forming a silicon layer, which is capable of improving crystalline fraction and uniform grain distribution of a silicon crystal, and to a method of manufacturing a display substrate using the same.